25-Hydroxyvitamin D2 and D3, Serum
Reporting Name
25-Hydroxyvitamin D2 and D3, SSynonym: Vit D Fractionated
Useful For
Diagnosis of vitamin D deficiency
Differential diagnosis of causes of rickets and osteomalacia
Monitoring vitamin D replacement therapy
Diagnosis of hypervitaminosis D
Performing Laboratory

Specimen Type
SerumSpecimen Required
Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Specimen Volume: 0.5 mL
Specimen Minimum Volume
0.25 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum | Refrigerated (preferred) | 14 days | |
Frozen | 30 days | ||
Ambient | 7 days |
Reference Values
TOTAL 25-HYDROXYVITAMIN D2 AND D3 (25-OH-VitD)
<10 ng/mL (severe deficiency)*
10-19 ng/mL (mild to moderate deficiency)**
20-50 ng/mL (optimum levels)***
51-80 ng/mL (increased risk of hypercalciuria)****
>80 ng/mL (toxicity possible)*****
*Could be associated with osteomalacia or rickets
**May be associated with increased risk of osteoporosis or secondary hyperparathyroidism
***Optimum levels in the healthy population; patients with bone disease may benefit from higher levels within this range
****Sustained levels >50 ng/mL 25OH-VitD along with prolonged calcium supplementation may lead to hypercalciuria and decreased renal function
*****80 ng/mL is the lowest reported level associated with toxicity in patients without primary hyperparathyroidism who have normal renal function. Most patients with toxicity have levels >150 ng/mL. Patients with renal failure can have very high 25-OH-VitD levels without any signs of toxicity, as renal conversion to the active hormone 1,25-OH-VitD is impaired or absent.
These reference ranges represent clinical decision values, based on the 2011 Institute of Medicine report, that apply to males and females of all ages, rather than population-based reference values. Population reference ranges for 25-OH-VitD vary widely depending on ethnic background, age, geographic location of the studied populations, and the sampling season. Population-based ranges correlate poorly with serum 25-OH-VitD concentrations that are associated with biologically and clinically relevant vitamin D effects and are therefore of limited clinical value.
For SI unit Reference Values, see https://www.mayocliniclabs.com/order-tests/si-unit-conversion.html
Day(s) Performed
Monday through Friday
Tuesday, Friday (Specimens on patients who are less than 1 year old)
Test Classification
This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
82306
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
25HDN | 25-Hydroxyvitamin D2 and D3, S | 49590-3 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
2897 | 25-Hydroxy D2 | 49054-0 |
2898 | 25-Hydroxy D3 | 1989-3 |
83670 | 25-Hydroxy D Total | 62292-8 |
Method Description
Deuterated stable isotope is added as internal standard. 25-Hydroxyvitamin D2 (25-OH-VitD2), 25-hydroxyvitamin D3 (25-OH-VitD3), and the internal standard are extracted. The extracts are then derivatized before being analyzed by liquid chromatography-tandem mass spectrometry using multiple reaction monitoring. 25-OH-VitD2 and 25-OH-VitD3 are quantified and reported individually and as a sum with a clinical reference range attached to the sum. For children under 1 year of age, a modified assay is performed to identify and eliminate interference due to C-3 epimers of 25-OH-VitD2 and 25-OH-VitD3.(Zimmer D, Pickard V, Czembor W, Muller C: Comparison of turbulent-flow chromatography with automated solid-phase extraction in 96-well plates and liquid-liquid extraction used as serum sample preparation techniques for liquid chromatography-tandem mass spectrometry. J Chromatogr A 1999 Aug 27;854[1-2]:23-35)
Report Available
2 to 5 daysReject Due To
Gross hemolysis | OK |
Gross lipemia | OK |
Gross icterus | OK |
Method Name
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
Forms
If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
-General Request (T239)
-Renal Diagnostics Test Request (T830)